consists of a series of fine non-vascular lamelle, each containing a delicate network 
of elastic fibres, amongst which are stellate, pigmented cells, together with ameeboid 
cells’ The spaces between the lamine are lined with endothelium, and together 
form the spatium perichorioideale, already referred to (p. 683). 
The proper tissue of the chorioid consists of blood-vessels and numerous pigmented 
cells, supported by connective tissue and elastic fibres, together with some smooth 
muscular fibres Its outer part contains the larger blood-vessels and is named the 
lamina vasculosa, while its inner portion is composed of a network of fine capillaries, 
and is termed the 
lamina choriocapillaris ; 
these two lamine are — 
joined by a thin inter- 
Canal of Schlemm. mediate stratum. The 
Cireulus arteriosus arteries of the chorioid 
py are derived from the 
Conjunctival vests Short posterior ciliary 
Recurrent artery vessels, which pierce 
CRONE 
Rakenos the sclera around the 
cores optic entrance and 
form a wide-meshed 
plexus in the lamina’ 
vasculosa. Their cir- 
cular muscular coat is 
well developed, and 
longitudinal muscular 
fibres are also present 
Capillaries of choroid in the larger branches. 
The veins, destitute of 
muscular tissue, are 
superficial te the 
arteries; they are 
surrounded by per- 
vascular lymphatie 
sheaths and converge 
to form whorls, which 
open into the venzvor-_ 
tacose. In the tissue 
Short posterter ciliary artery between the blood-_ i 
vessels are numerous 
stellate, flattened, and 
; pigmented cells. 
\iamer vessels of opite sheath The lamina chorio-— 
Dptie perre capillaris, or membrane 
Central artery and vein of retina of Ruysch, is com 
essentially of small — 
capillaries, which form — 
an exceedingly close network, embedded in a finely granular or almost homogeneous 
tissue. The intermediate stratum between the lamina vasculosa and lamina chorio- y 
eapillaris consists of a network of delicate elastic fibres and contains almost no : 
pigment cells: it is lined next the lamina choriocapillaris by a continuous layer of 
endothehum. al 
The lamina basalis. or membrane of Bruch, is transparent and nearly structure-_ 
less Its outer surface presents a trellislike network of fibres, which unite lt to 
the membrane of Ruysch, while its inner surface is smooth and is im contact with 
the pigmented layer of the retina. .. 
Tapetam—In many animals a brilliant iridescent a pearance is seen on the postero-external 
part of the chorioid, to which the name tapetam is pe Absent in man, it may be due, as 
im the horse, t0 a markedly fibrous condition of the stratum intermedium (tapetum fibrosum), ar, 
as in the seal, to the presence of some five or six layers of flattened iridescent cells lying imme- 
Giately outside the lamina chorioeapillaris (tapetum cellulosum). 
gus posemer ciliary artery 
Pre. £98 —Drachaw oF ree Creccnarrey oy THE Ev= (Leber). 
